Precision Measurements of the Triplet and Singlet Positronium Decay Rates

Abstract

Positronium (Ps) is the hydrogen-like bound state of the electron and its antiparticle, the positron. Positronium is an attractive testing ground for the theory of quantum electrodynamics (QED) since its constituent particles interact to high order only through the electromagnetic interaction. Fundamental tests of QED involving Ps may be classified as measurements of either fine structure in the n=1 or n=2 levels or of annihilation decay properties. After a brief overview, the precision measurement of the triplet and singlet ground state decay rates will be discussed.